Knee Extension Angle Research Articles

Comparison of the clinical outcomes following total knee arthroplasty in osseous ankylosed and non-ankylosed knees using propensity-score matching.

Few studies have compared the clinical outcomes and complications of total knee arthroplasty (TKA) in patients with and without osseous ankylosed knees. Thus, we investigated the clinical outcomes and complications of TKA in patients with osseous ankylosed knees using a propensity-score matching method. Thirteen knees in the osseous ankylosed-knees group and 13 knees in the non-ankylosed-knees group were included after excluding those with less than 2 years of follow-up or a lack of data and after propensity-score matching. The American Knee Society Score-knee (AKSS-knee), AKSS-function, knee-flexion angle, knee-extension angle, knee range of motion (ROM) before and after TKA, and the number of knees with postoperative complications were evaluated as primary outcomes. The AKSS-knee, AKSS-function, knee-flexion angle, and knee ROM in the osseous ankylosed-knees group after TKA were significantly lower than those in the non-ankylosed-knees group. The knee-extension angle after TKA and number of knees with postoperative complications within 2 years were not significantly different between the two groups. The clinical results of TKA in patients with osseous ankylosed knees were inferior to those in patients with non-ankylosed knees.

Effects of Speed and Amplitude of Dynamic Stretching on the Flexibility and Strength of the Hamstrings.

Dynamic stretching for more than 90 seconds is useful for improving muscle strength, although dynamic stretching for 30 seconds or less is commonly used in sports settings. The effects of dynamic stretching are influenced by the speed and amplitude of stretching, but no study examined these factors for 30 seconds of dynamic stretching. Therefore, the purpose of the present study was to examine the effects of speed (fast- or slow-speed) and amplitude (normal- or wide amplitude) of dynamic stretching for 30 seconds on the strength (peak torque during maximum isokinetic concentric contraction) and flexibility (range of motion, passive torque at maximum knee extension angle, and muscle-tendon unit stiffness) of the hamstrings. The passive torque and muscle-tendon unit stiffness reflect stretching tolerance and viscoelastic properties of the hamstrings, respectively. Fifteen healthy participants performed 4 types of 30 seconds of dynamic stretching. The muscle strength and flexibility were measured before and immediately after the dynamic stretching. The range of motion did not change after dynamic stretching at low speed and normal amplitude (p = 0.12, d = 0.59, 103.3%), but it was increased by other interventions (p < 0.01, d = 0.90-1.25, 104.5-110.1%). In all interventions, the passive torque increased (main effect for time, p < 0.01, d = 0.51 - 0.74, 111.0 - 126.9%), and muscle-tendon unit stiffness did not change. The muscle strength increased only after dynamic stretching at fast speed with normal amplitude (p < 0.01, d = 0.79, 107.1%). The results of the present study indicated that 30 seconds of dynamic stretching at fast speed and with normal amplitude can be beneficial for the measured parameters.

An impairment-specific hip exoskeleton assistance for gait training in subjects with acquired brain injury: a feasibility study

This study was designed to investigate the feasibility and the potential effects on walking performance of a short gait training with a novel impairment-specific hip assistance (iHA) through a bilateral active pelvis orthosis (APO) in patients with acquired brain injury (ABI). Fourteen subjects capable of independent gait and exhibiting mild-to-moderate gait deficits, due to an ABI, were enrolled. Subjects presenting deficit in hip flexion and/or extension were included and divided into two groups based on the presence (group A, n = 6) or absence (group B, n = 8) of knee hyperextension during stance phase of walking. Two iHA-based profiles were developed for the groups. The protocol included two overground gait training sessions using APO, and two evaluation sessions, pre and post training. Primary outcomes were pre vs. post-training walking distance and steady-state speed in the 6-min walking test. Secondary outcomes were self-selected speed, joint kinematics and kinetics, gait symmetry and forward propulsion, assessed through 3D gait analysis. Following the training, study participants significantly increased the walked distance and average steady-state speed in the 6-min walking tests, both when walking with and without the APO. The increased walked distance surpassed the minimal clinically important difference for groups A and B, (respectively, 42 and 57 m > 34 m). In group A, five out of six subjects had decreased knee hyperextension at the post-training session (on average the peak of the knee extension angle was reduced by 36%). Knee flexion during swing phase increased, by 16% and 31%, for A and B groups respectively. Two-day gait training with APO providing iHA was effective and safe in improving walking performance and knee kinematics in ABI survivors. These preliminary findings suggest that this strategy may be viable for subject-specific post-ABI gait rehabilitation.

Comparison of Tibial Tubercle Landmark Technique and Range of Motion Technique in Primary Total Knee Arthroplasty: A Retrospective Cohort Study.

There is not a standard for rotational alignment of the tibial component in total knee arthroplasty (TKA). For now, the most commonly methods are tibial-tubercle -landmark technique (TTL) and range-of-motion technique (ROM). The study is aimed to compare clinical outcomes and radiographic data of patients who undergone primary TKA with TTL or ROM technique. This single-surgeon retrospective cohort study includes 60 patients with TTL technique and 60 with ROM technique from December 2017 to January 2019. All patients were evaluated clinically using Hospital for Special Surgery Knee Score (HSS), Feller patellar score, visual analogue scale (VAS) and maximum knee flexion and extension angle before and after surgery at both 6 months and 12months postoperatively. Radiographic data contain hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), posterior slope angle (PSA) on pre and postoperative X-ray and rotation angle of femoral component (relative to surgical trans-epicondylar axis) and tibial component (relative to surgical trans-epicondylar axis, tibial posterior condylar line and Akagi') on postoperative computed tomography (CT) scan. Clinical outcomes and radiological data were compared between the two groups. One hundred twenty patients (120 knees) were enrolled in this study, including 38 males and 82 females, aged from 58 to 78, with an average of 65.7 years. There was no significant difference in demographics and preoperative X-ray data between the two groups (P > 0. 05). Clinical scores of the TTL group were better than those in the ROM group at 6 and 12months after surgery, when comparing HSS (83.57 ± 5.00 vs 75.90 ± 4.89, F=59.004, P < 0.001; 90.53 ± 4.31 vs 82.83 ± 4.98, F=54.509, P < 0.001), Feller patellar score (21.43 ± 2.54 vs 19.10 ± 2.52, F=14.864, P=0.001; 26.27 ± 1.98 vs 23.20 ± 2.31, F=42.204, P < 0.001) and VAS (3.70 ± 0.62 vs 4.38 ± 0.92, F=14.508, P=0.001; 2.10 ± 0.90 vs 2.79 ± 0.80, F=11.554, P=0.002). But there was no significant difference in the flexion and extension angle between the two groups. In imaging evaluation, no statistical difference was found in pre- and postoperative HKA, mLDFA, mMPTA and PSA. Rotational angles of tibial component only did relative to Akagi' have statistical difference in two groups (2.33 ± 4.3 vs 4.41 ± 3.2, t=2.143, P < 0.05) (Positive value represented external rotation). The results of our study showed that both methods were reliable, and TTL technique provided better clinical scores and larger external angle of tibial component, compared to ROM technique.

Gait Analysis of Bilateral Knee Osteoarthritis and Its Correlation with Western Ontario and McMaster University Osteoarthritis Index Assessment.

Background and objectives: Objective, accurate, and intuitive evaluation of knee joint function in patients with knee osteoarthritis (KOA) is important. This study aimed to clarify the gait characteristics of patients with bilateral KOA and their correlation with Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Materials and Methods: 20 patients with bilateral KOA and 20 conditionally matched healthy individuals were enrolled in the experimental and control groups, respectively. Footscan and CODA motion gait analysis systems were used to analyse the gait parameters. Gait spatiotemporal parameters and knee joint motion parameters were collected. Weight-bearing balance and walking stability were assessed using discrete trends of relevant gait indicators. Patients in the experimental group were evaluated using WOMAC. Pearson’s correlation analysis was performed on the gait data and WOMAC score data of the experimental group. Results: Velocity, cadence, step length, and stride length of the experimental group were significantly lower than those of the control group (p < 0.01). Step time and gait cycle were significantly greater in the experimental group than in the control group (p < 0.01). Total stance and double-stance times of the experimental group were significantly greater than those of the control group (p < 0.01), whereas the single-stance time was shorter than that of the control group (p < 0.01). The range of motion and maximum flexion angle in the experimental group were significantly lower than those in the control group (p < 0.01), and the minimum angle of knee extension was greater than that in the control group (p < 0.01). The discrete trend of weight-bearing balance and walking stability gait index in the experimental group was greater than that in the control group. The WOMAC score and gait analysis were significantly correlated (p < 0.05). Conclusions: The gait function of patients with KOA is significantly worse than that of normal people. The WOMAC scale and gait analysis can be used to assess KOA severity from different perspectives with good consistency.

Robotic ankle control can provide appropriate assistance throughout the gait cycle in healthy adults.

Ankle foot orthoses are mainly applied to provide stability in the stance phase and adequate foot clearance in the swing phase; however, they do not sufficiently assist during the entire gait cycle. On the other hand, robotic-controlled orthoses can provide mechanical assistance throughout the phases of the gait cycle. This study investigated the effect of ankle control throughout the gait cycle using an ankle joint walking assistive device under five different robotic assistance conditions: uncontrolled, dorsiflexion, and plantar flexion controlled at high and low speeds in the initial loading phase. Compared with the no-control condition, the plantar flexion condition enhanced knee extension and delayed the timing of ankle dorsiflexion in the stance phase; however, the opposite effect occurred under the dorsiflexion condition. Significant differences in the trailing limb angle and minimum toe clearance were also observed, although the same assistance was applied from the mid-stance phase to the initial swing phase. Ankle assistance in the initial loading phase affected the knee extension and ankle dorsiflexion angle during the stance phase. The smooth weight shift obtained might have a positive effect on lifting the limb during the swing phase. Robotic ankle control may provide appropriate assistance throughout the gait cycle according to individual gait ability.

Effects of running fatigue on lower extremity symmetry among amateur runners: From a biomechanical perspective.

The objective of this study was to examine the effects of running fatigue on the symmetry of lower limb biomechanical parameters in eighteen male amateur runners. The marker trajectories and ground reaction forces were collected before and after the running-induced fatigue protocol. Symmetry angles (SA) were used to quantify the symmetry of each parameter. Normality tests and Paired sample T-tests were carried out to detect bilateral lower limb differences and SA of parameters between pre- and post-fatigue. One-dimensional statistical parameter mapping (SPM_1d) was used to compare parameters with the characteristic of one-dimensional time series data of lower limbs. After fatigue, the SA of knee extension angles, knee abduction moment, and hip joint flexion moment increased by 17%, 10%, and 11% respectively. In comparison, the flexion angle of the knee joint decreased by 5%. The symmetry of internal rotation of ankle, knee and hip joints increased after fatigued, while the SA of external rotation of the three joints decreased significantly. These findings provide preliminary evidence that fatigue changes lower limb symmetry in running gait and may have implications for understanding running-related injuries and performance.

Acute Effects of Self-Myofascial Release Using Various Foam Rollers on Knee Extension Angles and Hamstring Muscle Tone in Subjects with Shortened Hamstrings : A Randomized Controlled Trial

This study aimed to compare the effects of hamstring self-myofascial release using three different foam rollers on the passive and active angles of knee extension and hamstring muscle tone in subjects with shortened hamstrings. Twenty subjects with shortened hamstrings were included. The passive and active knee extension angles and hamstring muscle tone were measured immediately after each self-myofascial release of the hamstring muscles using a soft-, hard-, or grid-type foam roller. A goniometer was used to measure the passive and active knee extension angles, while a Myoton PRO was used to measure the hamstring muscle tone. The passive and active knee extension angles significantly increased and the hamstring muscle tone significantly decreased after all interventions (p<.05). However, none of the dependent variables differed significantly among the three groups (p>.05). All soft-, hard-, and grid-type foam rollers effectively improved hamstring flexibility and muscle tone in subjects with shortened hamstrings. Our findings suggest that individuals should choose the foam roller that is comfortable for them.

Optimal intraoperative medial joint gap in extension to prevent flexion contracture following total knee arthroplasty using modified gap balancing technique

BackgroundPrimary aim to identify the ideal medial joint gap in extension needed to prevent post-operative flexion contracture following total knee arthroplasty (TKA) in varus osteoarthritic knees by the modified gap balancing technique. A secondary aim was to analyze multiple factors that influence knee extension in TKA by modified gap balancing. MethodsThis is a prospective cohort study of 150 patients diagnosed with osteoarthritic varus knee who underwent TKA using the modified gap balancing technique. Operative and clinical records were assessed to determine factors including age, BMI (Body mass index), pre-operative extension angle and the medial extension laxity. Patients were followed for 6-months post-operatively and reviewed for knee extension angle. ResultsSix months final follow-up information was available for 148 patients with an average age of 75.5 years. Pre-operative knee extension and BMI were significantly associated with post-operative knee extension. Post-operative flexion contracture of ≧ 100 was not seen in any of 34 patients with a medial extension laxity ≧ 0 mm who had no pre-existing flexion contracture, and in 1/9 (11.1%) patients with a medial extension laxity ≧ 1 mm who had pre-existing flexion contracture. ConclusionsPre-operative extension angle and BMI significantly influence the post-operative knee extension angle in TKA using the modified gap balancing technique. A medial extension laxity of at least 1 mm is ideally needed to prevent post-operative flexion contracture in patients with a pre-existing contracture ≧ 100. Level of evidenceLevel II; Prospective cohort study.

Influence of posterior tibial slope on sagittal knee alignment with comparing contralateral knees of anterior cruciate ligament injured patients to healthy knees

Posterior tibial slope (PTS) has been known to contribute to anterior–posterior knee stability and play an essential biomechanical role in knee kinematics. This study aimed to investigate the effect of PTS on single-leg standing sagittal knee alignment of the intact knee. This study included 100 patients with unilateral ACL injury knee (ACL injury group, 53 patients) or with the normal knee (control group, 47 patients). The single-leg standing sagittal alignment of the unaffected knees of the ACL injury group and normal knees of the control group were assessed radiographically with the following parameters: knee extension angle (EXT), PTS, PTS to the horizontal line (PTS-H), femoral shaft anterior tilt to the vertical axis (FAT), and tibial shaft anterior tilt to the vertical axis (TAT). PTS was negatively correlated with EXT and positively correlated with TAT. EXT was significantly larger in the ACL injury group, whereas TAT was smaller in the ACL injury group. Patients with larger PTS tend to stand with a higher knee flexion angle by tilting the tibia anteriorly, possibly reducing tibial shear force. Patients with ACL injury tend to stand with larger EXT, i.e., there is less preventive alignment to minimize the tibial shear force.

Single-stage arthroscopic-assisted treatment of anteromedial tibial plateau fracture with posterolateral corner injury: a retrospective study.

BackgroundAnteromedial tibial plateau fracture with posterolateral corner (PLC) injury is a relatively rare combined injury in the clinic. In addition, there is no unified treatment scheme for this combined injury. The purpose of this study was to evaluate the clinical and imaging results of single-stage arthroscopic-assisted surgery for anteromedial tibial plateau fracture with PLC injury, and to explore the advantages of this surgical technique.MethodIn this retrospective study, a total of 9 patients (7 males and 2 females) were included, aged 24–64 years (average 40.7 years), treated in our Department of Orthopedics from January 2016 to January 2021. In the preoperative evaluations, there were 9 cases of anteromedial tibial plateau fractures with PLC injuries, 6 cases of concomitant PCL injuries, 6 cases of concomitant medial or lateral meniscus injuries, and 2 cases of concomitant fibular head avulsion fractures. All patients underwent single-stage arthroscopic-assisted surgery.ResultsAll patients were followed up, and the average follow-up period was 15.2 months (range 12–18 months). The average operation time was 135.6 min (range 100–160 min), and the average surgical blood loss was 87.2 ml (range 60–110 ml). The anatomical reduction was achieved in 9 cases, and the anatomical reduction rate was 100%. The average fracture healing time was 13.1 weeks (range 12–16 weeks). At the last follow-up, the average VAS score was 1 (range 0–2); the average Lysholm function score was 90.7 (range 86–95), and the average IKDC score was 91.4 (range 88–95); the average knee extension angle of all patients was 0° and the average knee flexion angle was 128.3° (average 120–135°); The posterior drawer test, the Lachman test and the dial test were negative for all cases. None of the patients had operation-related complications.ConclusionSingle-stage arthroscopy-assisted surgery in the treatment of anteromedial tibial plateau fracture with PLC injury can achieve good clinical outcomes, restore the stability of the knee joint, and reduce the risk of severe lower extremity dysfunction.

A comparative study of instep kicking swings, ball impacts, and ball speeds in male and female football players

This research aims to compare swings, ball impacts, and ball velocities of instep kick between male and female players. The research used comparative design method, in which two groups of males and females were compared. This research used eight Indonesian football players as sample: four males and four females. The instrument used for data collection in this research is football long pass test. Video documentation was taken with high-speed camera unit with 1000 fps ability. The data collected were then analyzed through Kinovea, in which swing angles, foot angular velocities, ball impact times, ball velocities, and resulting ball distances were calculated. Non-parametric Mann-Whitney test were used to compare each instep kick of male and female players. Results show that no difference on instep long pass swing and ball impact between male and female players was observed. On average, male players performed instep kicking with kicking foot knee flexion angle of 104.750, hip angle of 77.250, kicking foot knee extension angle of 1580, kicking foot steepness angle of 58.250, average power of 209.38 J/s (watt), and average kicking foot angular velocity of 0.11 rad/s, which resulted in average ball impact of 10.27 Ns that caused average post-impact ball velocity of 22.83 m/s and average ball distance of 26.63 meters. Meanwhile, female players performed instep kicking with kicking foot knee flexion angle of 930, hip angle of 74.250, kicking foot knee extension angle of 1480, kicking foot steepness angle of 56.250, average power of 237.28 J/s (watt), and average kicking foot angular velocity of 0.11 rad/s which resulted in average ball impact of 10.32 Ns that caused average post-impact ball velocity of 22.94 m/s and average ball distance of 26.87 meters. The results show that the average ball distance of male players was closer to 25-meter target than those of female players. In order to achieve 25-meter kicking accuracy, female players contributed greater power and steeper kicking foot angle than their male counterparts. In conclusion, to master instep kicking technique, female players need to pay attention to their power and body position during kicking.

Short Term Effects of Remote Myofascial Release versus Mulligan’s Bent Leg Raise on Hamstring and Lumbar Spine Flexibility in College Going Students: An Experimental Study

Background: Hamstring flexibility is an important factor because reduced flexibility is being considered as a predisposing factor for idiopathic low back pain. Considering the pelvis to be base of the spine, its orientation affects the lumbar lordotic curvature. Hence, it can be postulated that hamstring flexibility is influenced by pelvic posture.The aim of the study was to evaluate and compare the short term effects of Remote myofascial release (bilateral plantar fascia) and Mulligan’s bent leg raise on hamstring and lumbar spine flexibility in college going students.Method: Total 78 students were recruited for the study as per selection criteria and were divided into two groups (39 in each group). Group A was treated with Remote myofascial release (bilateral plantar fascia) and group B was treated with Mulligan’s bent leg raise for 6 days (daily 1 session of 3 repetitions). Inter-group analysis by unpaired t-test showed statistically significant improvement on knee extension angle test, sit and reach test and lumbar lordosis index (P value ≤ 0.05).Conclusion: Remote myofascial release as well as Mulligan’s bent leg raise were beneficial in improving hamstring and lumbar spine flexibility. However, Mulligan’s bent leg raise was found to be more effective in hamstring and lumbar spine flexibility

Effect of Salat Activity on Knee Pain, Range of Motion and Muscle Strength After Total Knee Arthroplasty: A Single-Blinded Randomized Controlled Trial.

Objectives: The aim of this study was to investigate the effect of salat activity on knee pain, muscle strength and range of motion after posterior stabilized total knee arthroplasty.&#x0D; Material and Methods: This prospective randomized study was conducted in KTO Karatay University and Medova Hospital, Konya, Turkey, between March 2019 and June 2019. Thirty volunteers between the ages of 55 and 75 who had undergone total knee arthroplasty participated in this study. Participants were randomly divided into two groups as physical therapy group and physical therapy + salat group. The participants in the physical therapy group were provided hot-cold application, transcutenous electrical nerve stimulation (TENS), active-assisted range of motion, stretching and strengthening exercises during four weeks. Physical therapy+salat group performed salat activity in addition to the treatment. The knee joint patency was measured using a digital goniometer, muscle strength using a manual muscle tester, knee pain with the visual analogue scale (VAS).&#x0D; Results: There was no difference in knee flexion and extension muscle strength between the groups before and after treatment (p ˃ 0.05). There was no difference in VAS values between the groups before and after treatment (p ˃ 0.05). Knee flexion angle increased significantly in the physical therapy+prayer group compared to the post-treatment physical therapy group (p˂0.003). There was no significant difference between the groups in knee extension angle before and after treatment (p˃0.05).&#x0D; Conclusion: In this study, it was found that Salat activity after knee arthroplasty improved knee joint range of motion.

Effects of Soccer Exercise on Balance Ability and Kinesthesia of the Lower Limb Joints in Children Aged 5-6 Years.

Age-, height- and weight-matched children were recruited to the experimental group (EG; n = 31) and control group (n = 32). Following a 16-week soccer training program, balance ability and dominant-side lateral knee and ankle kinesthesia changes were tested. Regarding balance ability, the Sway Index, when children stood on a firm or foam surface with their eyes closed in the static balance test, and the dynamic balance test time were 13.5%, 11.6%, and 14.3% lower in the EG than in the control group, respectively. The scores in the left and right directions were 23.7% and 24.2% higher in the EG, respectively. Regarding kinesthesia, the angle of knee extension and ankle metatarsal flexion and dorsiflexion were 13.4%, 20.0%, and 16.8% lower in the EG than in the control group. These results indicate children in the EG had a better performance. After soccer exercise, children aged 5-6 years displayed improved balance in the left and right directions and improved knee extension, ankle plantarflexion, and dorsiflexion kinesthesia.

Feasibility and Effect of a Wearable Motion Sensor Device in Facilitating In-Home Rehabilitation Program in Patients after Total Knee Arthroplasty: A Preliminary Study

Postoperative home-based rehabilitation programs are essential for facilitating functional recovery after total knee replacement (TKA). This study aimed to verify the feasibility of applying a wearable motion sensor device (MSD) to assist patients in performing home-based exercises after TKA. The interrater reliability of the measurement for knee mobility and the time spent completing the 5-times sit-to-stand test (5TSST) by two experienced physicians and using the MSD in 12 healthy participants was first assessed. A prospective control trial was then conducted, in which 12 patients following TKA were allocated to two groups: the home-based exercise group and the MSD-assisted rehabilitation group. Changes in knee range of motion, pain, functional score, performance, and exercise completion rates were compared between the groups over two months of follow-up. MSD-measured knee mobility and 5TSST exhibited excellent reliability compared with the physician measurements. Furthermore, patients in the MSD-assisted rehabilitation group reported higher training compliance than participants in the home-based exercise group, which led to better outcomes in the knee extension angle and maximal and average angular velocity in 5TSST. MSD-assisted home-based rehabilitation following TKA is a feasible treatment model for telerehabilitation because it enhances patients’ compliance to training, which improves functional recovery.

Acute effects of small changes in antero-posterior shoe-cleat position on physiological and biomechanical variables in road cycling

ABSTRACT The aim of this study was to investigate the effect of changes in cycling shoe-cleat position on pedalling biomechanics, physiological variables, and performance in road cycling. Twelve competitive road cyclists performed three pedalling trials with the cleat positioned at the first metatarsal head, 15-mm anterior and 15-mm posterior. Each trial included three sets of 5 min performed at 35%, 50%, and 65% of maximal aerobic power (MAP) followed by a 10-s sprint. Results showed no significant changes in physiological variables, pedalling kinetics, muscular activity of six lower limb muscles, sprint performance and perceived exertion. However, significant differences were found regarding joint kinematics: hip, knee, and ankle angles during both extension and flexion were reduced in the anterior cleat position. Therefore, this study suggests that cleat position does not affect sprint performance, physiological variables, pedalling kinetics, muscle activity, and perceived exertion regardless of the cycling intensity. However, joint kinematics, and particularly knee extension angle which could be related to the risk of overuse injuries, was affected by the shoe-cleat position.

Lower Limb Biomechanics During Drop-Jump Landings on Challenging Surfaces in Individuals With Chronic Ankle Instability.

Individuals with chronic ankle instability (CAI) exhibit impaired lower limb biomechanics during unilateral drop-jump landings on a flat surface. However, lower limb biomechanical adaptations during unilateral drop-jump landings on more challenging surfaces, such as those that are unstable or inclined, have not been described. To determine how unilateral drop-jump landing surfaces (flat, unstable, and inclined) influence lower limb electromyography, kinematics, and kinetics in individuals with CAI. Descriptive laboratory study. Biomechanics laboratory. A total of 22 young adults (age = 24.9 ± 4.9 years, height = 1.68 ± 0.08 m, mass = 70.6 ± 11.4 kg) with CAI. Participants completed 5 trials each of unilateral drop-jump landings on a flat surface (DROP), an unstable surface (FOAM), and a laterally inclined surface (WEDGE). Electromyography of the gluteus medius, vastus lateralis, gastrocnemius medialis, peroneus longus, and tibialis anterior muscles was recorded. Ankle and knee angles and moments were calculated using a 3-dimensional motion-analysis system and a force plate. Biomechanical variables were compared among tasks using 1-dimensional statistical nonparametric mapping. During DROP, greater ankle-dorsiflexion and knee-extension moments were observed than during FOAM and WEDGE and greater vastus lateralis muscle activity was observed than during FOAM. Greater ankle-inversion and plantar-flexion angles were noted during FOAM and WEDGE than during DROP. Peroneus longus muscle activity was greater during DROP than during FOAM. During FOAM, greater ankle-inversion and knee-extension angles and ankle-inversion and internal-rotation moments, as well as less peroneus longus muscle activity, were present than during WEDGE. The greater ankle-inversion and plantar-flexion angles as well as the lack of increased peroneus longus muscle activation during the FOAM and WEDGE conditions could increase the risk of recurrent lateral ankle sprain in individuals with CAI. These findings improve our understanding of the changes in lower limb biomechanics when landing on more challenging surfaces and will help clinicians better target deficits associated with CAI during rehabilitation.

The acute effects of different hamstring muscle stretching techniques on reducing muscle resistance to movement by ultrasound elastography

ObjectiveMany stretching methods are applied on the hamstring muscles for reducing muscle resistance on movement. The aim of our study to investigate the acute effects of static stretching and the Mulligan traction straight leg raise (TSLR) technique administered to the hamstring muscles on reducing its resistance to movement. MethodsThe study included 22 healthy male volunteers (19.5 ± 0.98 years). After the individuals were randomly divided into two groups, static stretching was administered to the hamstring muscles in the first group and the Mulligan TSLR technique was administered on the same muscle in the second group. Active knee extension angles of the individuals were evaluated by a digital goniometer and muscle strain was assessed by ultrasound elastography. ResultsWhile there was a significant difference in all parameters in both groups after the treatment, the changes in the active knee extension angle and the strain index value of the biceps femoris musculotendinous junction were higher in the Mulligan TSLR group compared to the static stretching group (p < 0.05). ConclusionIt was concluded that, static stretching and the Mulligan TSLR technique administered to the hamstring muscles are effective ways to increase the range of motion. The Mulligan TSLR technique, however, can be opted in healthy individuals and patients since it is painless and more effective in reducing muscle resistance to movement and range of motion.

Biomechanics analysis on Jejag kick of pencak silat.

The force in the pencak silat jejag kick is called the moment of force or torque. The force moment is a measure of the force that can cause an object to rotate around the axis where the axis of rotation is located at the knee joint with the length of the calf as the length of the arm (the radius of the rotation axis). This research was conducted using laboratory biomechanical analysis. The research sample consisted of three male athletes of pencak silat. Previously, anthropometric measurements were carried out in the form of measuring calf length and calf muscle mass, then taking videos of athletes doing jejag kick movements in a static state with targets, which were then analyzed by kinovea. Research results showed that the technique of the jejag kick pencak silat produces a force called the moment of force or torque. Sample 1 produces a force moment of -12.00 Nm, sample 2 produces -5.53 Nm, and sample 3 produces -8.73 (negative sign means the direction of the pencak silat jejag kick is counterclockwise). The magnitude of the force moment is influenced by the angle of knee extension and the radius of the rotation axis. The amount of force moment affects the kick speed. In the speed of a movement, there is a tendency to keep moving, which is called the moment of inertia. The fasterthe movement, the greater the moment of inertia. The result is a force moment, influenced by the rotational kinetic energy that is owned and requires effort. Every effort is made to produce a force moment; it takes power to drive the effort. This means that the greater the angle of extension and the longer the calf, the greater the force moment, the faster the kick speed, and the greater the moment of inertia. This requires a large amount of rotational kinetic energy, effort, and power.